meiosis v mitosis
Here are college-level flashcards comparing mitosis and meiosis. I formatted them as Q = front of card, A = back of card.
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FLASHCARDS — MITOSIS vs. MEIOSIS (College Level)
1⃣ What is the purpose of mitosis?
Answer:
Mitosis produces genetically identical somatic (body) cells for growth, tissue repair, and asexual reproduction. It maintains chromosome number (2n → 2n) and ensures each daughter cell receives an exact copy of the parent genome through highly regulated stages involving spindle microtubules and checkpoint controls.
2⃣ What is the purpose of meiosis?
Answer:
Meiosis produces haploid gametes (n) for sexual reproduction and increases genetic variation through recombination and independent assortment. It involves two sequential divisions (Meiosis I and II) and reduces chromosome number from diploid to haploid (2n → n).
3⃣ What type of cells undergo mitosis?
Answer:
Somatic (non-reproductive) cells undergo mitosis. These include skin, muscle, and internal organ cells, all of which require genetically identical daughter cells to maintain tissue function and integrity.
4⃣ What type of cells undergo meiosis?
Answer:
Germ cells in the gonads undergo meiosis to form gametes—sperm or eggs. These specialized precursor cells enter meiotic divisions during gametogenesis.
5⃣ What happens during Prophase of mitosis?
Answer:
Chromatin condenses into visible chromosomes, the nuclear envelope breaks down, centrosomes migrate to opposite poles, and the mitotic spindle begins to form. No homologous pairing or crossing over occurs.
6⃣ What happens during Prophase I of meiosis?
Answer:
Homologous chromosomes pair via synapsis, forming tetrads. Crossing over occurs at chiasmata, exchanging DNA between non-sister chromatids. This is the main source of recombination. Prophase I is the longest and most complex stage of meiosis.
7⃣ What is crossing over?
Answer:
A process during Prophase I where non-sister chromatids exchange DNA segments. This produces recombinant chromosomes and increases genetic diversity. It requires the synaptonemal complex and double-strand break repair enzymes.
8⃣ How do chromosomes line up in Metaphase of mitosis?
Answer:
Individual chromosomes (each consisting of two sister chromatids) align at the metaphase plate. There is no pairing of homologous chromosomes.
9⃣ How do chromosomes line up in Metaphase I of meiosis?
Answer:
Tetrads (paired homologs) line up at the metaphase plate. The orientation of each homologous pair is random—this is independent assortment, another source of genetic variation.
🔟 What is separated in Anaphase of mitosis?
Answer:
Sister chromatids are pulled apart by spindle microtubules to opposite poles. After separation, each chromatid becomes an individual chromosome.
1⃣1⃣ What is separated in Anaphase I of meiosis?
Answer:
Homologous chromosomes (not sister chromatids) are separated and pulled to opposite poles. Sister chromatids remain attached at their centromeres until Meiosis II.
1⃣2⃣ What is separated in Anaphase II of meiosis?
Answer:
Sister chromatids are finally separated, similar to mitosis. However, the cells are haploid, so each resulting chromatid becomes a distinct haploid chromosome.
1⃣3⃣ How many daughter cells result from mitosis?
Answer:
Two diploid, genetically identical daughter cells.
1⃣4⃣ How many daughter cells result from meiosis?
Answer:
Four haploid, genetically distinct gametes due to recombination and independent assortment.
1⃣5⃣ How does genetic diversity differ between mitosis and meiosis?
Answer:
Mitosis preserves genetic identity, producing clones.
Meiosis generates diversity through crossing over, random orientation of homologs, and random fertilization.
1⃣6⃣ How do spindle fibers differ in their function between mitosis and meiosis?
Answer:
In mitosis, spindle fibers attach to sister chromatids individually.
In Meiosis I, spindle fibers attach to homologous chromosome pairs, ensuring reductional division. In Meiosis II, spindle function resembles mitosis.
1⃣7⃣ What is the ploidy change in mitosis vs meiosis?
Answer:
Mitosis: 2n → 2n (no change).
Meiosis: 2n → n (chromosome reduction to form gametes).
1⃣8⃣ What key checkpoints regulate mitosis?
Answer:
G1 checkpoint (DNA damage, cell size, nutrients)
G2 checkpoint (DNA replication completeness)
M checkpoint (spindle attachment before anaphase)
Failure leads to cell cycle arrest or apoptosis.
1⃣9⃣ What key checkpoints regulate meiosis?
Answer:
Meiotic recombination checkpoint (ensures proper synapsis & crossover formation)
Spindle assembly checkpoints in both Meiosis I & II
Improper control can lead to nondisjunction and aneuploidies (e.g., trisomy 21).
2⃣0⃣ What is nondisjunction and in which process is it more likely?
Answer:
Nondisjunction is the failure of chromosomes or chromatids to separate properly. It is more common in meiosis, especially in oocytes, and leads to disorders like Down syndrome, Turner syndrome, and Klinefelter syndrome.
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